1. Field of the Invention
The present invention pertains to an automatic vehicle, and more particularly, to an automatic vehicle that can move along a target object.
2. Description of the Related Art
Various vehicles that perform certain work such as the cleaning and transportation of goods while moving along a target object such as a wall have been proposed as automatic vehicles that automatically move while detecting obstacles around them.
For example, Japanese Laid Open Patent Hei 4-84207 discloses an automatic vehicle that moves along the contour of the wall on one side.
Japanese Laid Open Patent Hei 3-160507 discloses an automatic vehicle equipped with distance measuring sensors placed on either side, one sensor in front of the other, which obtains its own position and orientation from the distance between itself and the wall as detected by the front and back distance measuring sensors, and thereby moves along the contour of the wall.
Japanese Laid Open Patent Hei 5-17703 discloses an automatic vehicle that measures the distance between itself and a reference wall, and is controlled such that it moves along a predetermined travel route. This automatic vehicle has two pairs of distance measuring sensors: one pair at one side of the vehicle and one pair at the center of the vehicle. The distance measuring sensors at the center of the vehicle perform close range distance measurement, and the distance measuring sensors at the side of the vehicle perform longer range distance measurement.
Japanese Laid Open Patent Hei 4-260905 discloses a model in which a contact wall detecting switch is placed at the tip of a working arm and the position of the working arm is adjusted such that this wall detecting switch is in contact with the wall at all times in order to ensure that the work is performed while the arm is in close contact with the wall.
Also disclosed is an automatic vehicle that can move straight ahead without being influenced by concavities on the wall surface, by virtue of placing members that indicate the concavities inside the concavities and making the vehicle move straight ahead based on said members.
However, pertaining to the automatic vehicle of Japanese Laid Open Patent Hei 4-84207, since distance measurement is performed to the wall on one side only, where the automatic vehicle is not parallel to the wall, it cannot move accurately along the contour of the wall.
With regard to the automatic vehicle of Japanese Laid Open Patent Hei 3-160507, where the automatic vehicle itself is small and is short in length, the front and rear distance measuring sensors cannot be placed at a sufficient distance from each other, and as a result the position and orientation of the automatic vehicle cannot be measured with high accuracy.
In the automatic vehicle disclosed in Japanese Laid Open Patent Hei 5-17703, the distance measuring sensors for longer range measurement are located at the center of the vehicle at a distance from the other pair, and consequently the automatic vehicle needs to have a certain minimum width and cannot be made small.
In regard to Japanese Laid Open Patent Hei 4-260905, because the wall detecting switch is placed on the working arm, where there is a protrusion on the wall, the working arm may get stuck, preventing the movement of the vehicle along the contour of the wall.
On the other hand, when using the model that requires the mounting of members that indicate concavities in the surface of the wall, said members need to be mounted in advance in accordance with the changes in the wall surface, the target object. Therefore, it is not possible for the automatic vehicle of this type to automatically move along the contour of a target object of all types of configuration.